Improved properties and processability of polycarbonate has been disclosed in U.S. Pat. No. 3,130,177 and U.S. Pat. No. 3,162,695 to result upon the blending therewith a butadiene graft polymer; blends of polycarbonate and polyester, modified by a butadiene graft copolymer were disclosed in U.S. Pat. No. 3,864,428. Also, similar systems were disclosed in U.S. Pat. No. 4,180,494 to offer improved solvent resistance.
The present invention is based on the surprising and unexpected level of impact strength, especially at low temperatures, associated with a particular composition comprising polyalkylene terephthalate and polycarbonate resins having a certain weight ratio therebetween and a particular graft elastomer which is characterized in that its elastomeric core is predominantly of polybutadiene.